httpimg (php)

<?php
function getext($filename) {
    $pos = strrpos($filename,'.');
    $str = substr($filename, $pos);
    return $str;
}
$image = $_POST["image"];
$size = exif_imagetype($image);
$scalew = 1 / $_POST["scaleW"];
$scaleh = 1 / $_POST["scaleH"];
$ext = getext($image);
if($size == IMAGETYPE_JPEG){
    $img = ImageCreateFromJPEG($image);
} else if($size == IMAGETYPE_PNG){
    $img = ImageCreateFromPNG($image);
} else if($size == IMAGETYPE_GIF){
    $img = ImageCreateFromGIF($image);
} else if($size == IMAGETYPE_BMP){
    $img = ImageCreateFromBMP($image);
} else {
    echo'Wrong File Type';
}
$width = imagesx($img);
$height = imagesy($img);

for($h=0;$h<$height;$h=$h+$scaleh){
    if($h > 0){
                echo '
';
    }
    for($w=0;$w<=$width;$w=$w+$scalew){
        $rgb = ImageColorAt($img, floor($w), floor($h));
        $r = ($rgb >> 16) & 0xFF;
        $g = ($rgb >> 8) & 0xFF;
        $b = $rgb & 0xFF;
        $bright = ($r + $g + $b) / 3;
        if($w >= $width){
        } else {
            if($r > $g + 50 and $r > $b + 50){
            //Red
                if($bright >= 54){
                    echo "e";
                } else {
                    echo "c";
                }
           } else if($g > $r + 50 and $g > $b + 50){
           //Green
                if($bright >= 54){
                    echo "5";
                } else {
                    echo "d";
                }
            } else if($b > $r + 50 and $b > $g + 50){
            //Blue
                if($bright >= 92){
                    echo "a";
                } else {
                    echo "b";
                }
           } else if($r > $b + 10 and $g > $b + 10){
            //Red + Green
                if($bright >= 132){
                    echo "4";
                } else {
                    echo "1";
                }
            } else if($g > $r + 10 and $b > $r + 10){
            //Green + Blue
                if($bright >= 96){
                    echo "3";
                } else {
                    echo "9";
                }
            } else if($r > $g + 10 and $b > $g + 10){
            //Red + Blue
                if($bright >= 145){
                    echo "6";
                } else {
                    echo "2";
                }
           } else {
                if($bright >= 200){
                    echo "0";
                } else if($bright >= 130){
                    echo "8";
                } else if($bright >= 55){
                    echo "7";
                } else {
                    echo "f";
                }
           }

        }
    }
}
?>